All these are well known international IT Consultancies. I personally would go for Accenture first, Bearinpoint second and Cap last, but others may disagree.
Going to a Tier2, Tier3 or Boutique for a couple of years is definitely a solid strategy. You may like it and want to stay there, you may decide to go back to school for additional education, or you may try MBB again. Meanwhile, you will get a solid comp, good career development and great resume builder.
It doesn't look like you have much choice anyway, but these options you laid out are very sensible.